Mo Salah and Roberto Firmino scored two goals apiece with Sadio Mane also netting but Roma had a sting in the tail with two late goals.
THERE is no stopping Mo Salah. Surely there is no stopping Liverpool.
If they can hold their nerve inside the Olympic Stadium next week, they will reach the Champions League final.
There will be doubts, some recriminations – and rightly so – after gifting Roma two late goals at Anfield.
By then Liverpool had scored five, racing away with this first leg because Salah was at his compelling best.
He scored two and made two in a remarkable – and frankly ridiculous – Liverpool performance.
When Salah was substituted, Liverpool lost their rhythm.
It allowed Roma to sneak back into this semi-final, with Edin Dzeko scoring nine minutes from time and Diego Perotti jangling nerves with a penalty.
The return in Rome will be a test for Liverpool now.
They will be well aware of the pitfalls, the mistakes Barcelona made in the second leg in Italy after thrashing Roma 4-1 in the Nou Camp.
Liverpool are far too good to toss away a 5-2 lead.
They have the smell of the final, sniffing it out after this stunning, first leg win.
Salah had put Liverpool into a commanding 2-0 lead by half time and then wreaked havoc in the second.
He ended the night with two more assists, setting up Sadio Mane to make it 3-0 and then touching the ball in for Firmino to score the fourth.
Firmino, outstanding alongside Salah, headed Liverpool’s fifth beyond Allison when he connected with James Milner’s 69th minute corner.
Even when Dzeko chested down to beat Karius and Perotti scored penalty, the night still belonged to Liverpool.
Salah soothes nerves, settling fans and rewarded this expectant, raucous Anfield crowd with a breathtaking performance.
This was Salah at his ruthless, intimidating, brilliant best.
The newly-crowned PFA player of the year scored his first with a beauty off his left boot 36 minutes into this tie.
When he scored again, nonchalantly flicking Firmino’s through-ball beyond Allison, he was in the hunt for a hat-trick.
In the end he settled for two assists.
Salah, facing his former Roma team-mates for the first time since his move to Liverpool last summer, is walking with the giants of the game now.
He is closing in on Lionel Messi, closing in on Cristiano Ronaldo.
Salah, with 43 goals for the season, is not quite there just yet. But he is not far behind.
To score 11 in a Champions League season, to score in 10 successive games at Anfield, is a special achievement. He is a special player.
Cherish him, love him, respect him.
The Egyptian king is a game-changer, showing the composure of a world class footballer when Liverpool’s players were peppering Allison’s goal.
Firmino, Georginio Wijnaldum and Sadio Mane were all chasing the opening goal when Salah struck from the left.
It was a goal of haunting beauty, pinging off his left peg in super slo-mo after he cut in from the left.
He picked his spot, bending his effort beyond the reach of Roma’s highly-fancied keeper.
It set Liverpool on their way, with Jurgen Klopp pumping his fist on the touchline and demanding more from these Liverpool players.
He got it.
Salah responded, with Firmino setting it all up when these red men broke down another Roma attack at high-speed.
These boys switch positions at will, racing into different areas of the pitch as they carved open this leaky Roma defence with another counter.
That movement, that deceptive pace, made all the difference.
Firmino set it all up again, delaying his pass for long enough to set Salah clear of Roma’s defence.
The finish was exquisite and inevitable, lifting his effort beyond Allison as he raced out of his goal to close down the Liverpool forward.
This was a mighty performance from Liverpool.
With the exception of Aleksandr Kolarov’s belting effort that was palmed onto the cross bar by Loris Karius in the first half, Liverpool were unrivalled at times.
They were lifted by the Anfield crowd, feeding off the enthusiasm and the desire to emulate some of the great Liverpool teams.
Five European Cups could soon become six.
Jurgen Klopp called this just right, adopting the same unrelenting tactics that unseated Manchester City in the first leg of the quarter final at Anfield.
They were rewarded with another big result when Salah repaid Firmino for his first half assists by picking him out after 61 minutes.
By then they had scored a third, with Mane getting on the scoresheet after fluffing his lines in the first half.
Firmino scored the fifth, rising unchallenged above Roma’s leaden-footed defence to direct a header beyond Allison.
By the time Roma began the comeback, Salah was resting up on the bench.
Next week, when they travel to Italy, they will need him more than ever.